D’Agostino amp with Spectral preamp

The rule of thumb is the  input impedance of an amp should be at least 10x that of a preamp. It looks like there should be no problem!

There shouldn't be an impedance mismatch.  If I recall correctly Spectral preamps can work well with non-Spectral amps, but Spectral amps should always be used with Spectral preamps (and interconnects).  Spectral believes in wide bandwidth performance which can unsettle some equipment.  Good luck.

Thanks guys for you input. Sounds like I should tread carefully here. 

Spectral designs are ultra-wide bandwidth and really optimized when used in a system wide approach with their matched electronics and recommended cabling. It's more than an attempt to sell more of their gear, but with the instrumentation grade circuitry involved the networked cables are pretty much a requirement for their electronics to perform as they were designed and maintain stability. You will hear some reports of users who match a piece of Spectral gear with other brands but that's not the way to get them to perform at their peak level.